Exploration of both a post singularity Solar System and the transhuman state. How does this state alter how we see our existence? Is it an improvement or a detriment? What, if anything, does "human" mean now? Has becoming transbiological brought us closer to Nature, or pushed us further away from it? These are the themes, IMO, that draw people to EP as a setting. The questions (as the best themes are always questions) are what resonate in our heads and make us consider all the different possibilities that such a world (if you'll excuse the anachronism) would offer. As a game system, EP offers a simple mechanic with lots of old-school-rpg-style crunch. It works well for simulating transhuman action and adventure and doesn't require a PhD in number theory to play well. The core experience is exposure to and interaction with all the different transhuman states of existence - it's fighting TITAN remnants in the vacuum of a dead hab with a decaying orbit, it's trekking through the desolate Martian Outback to find your lost buddy before his backup 02 runs out, it's resleeving into a rented surya so you can find and speak with the last native speaker of Swahili, it's dumping your morph into a trash chute and hiding out as infolife in the dead sectors of the hab's subsystems while a Lost psychopath posing as an Ultimate hunts you in the dark. That, my friend, is Eclipse Phase.